When do tomatoes generally flower and set fruit? How should they be fertilized during the flowering and fruiting stages? What are the symptoms of nutrient deficiency and how should they be addressed?

Tomato, that is, the tomato, is also called fan shi and yang shi zi. Its plant height is 0.6-2 m, the whole plant bears sticky glandular hairs, and it has a strong odor. It is widely cultivated in both northern and southern China.So when do tomatoes generally flower and set fruit? How should they be fertilized during the flowering and fruiting stages? What are the symptoms of nutrient deficiency and how should they be addressed?According to Solanaceae data, the tomato inflorescence has a total peduncle 2-5 cm long, usually 3-7 flowers, a radiate calyx, a radiate corolla, and a fleshy, juicy berry that is oblate or nearly spherical, with yellow seeds; the flowering and fruiting period is summer and autumn.

When do tomatoes generally flower and set fruit?

The growth and development cycle of the tomato, from seed sowing and sprouting to the ripening of the seeds of the first truss, is the growth and development cycle. It is divided into 4 stages: the germination stage, the seedling stage, the flowering and fruit-setting stage, and the fruiting stage.

1. Germination stage

From seed sprouting to the emergence of the first true leaf from the two cotyledons is the development stage, generally 7-9 days.

2. Seedling stage

From the emergence of the first true leaf to the appearance of large flower buds is the seedling stage. At suitable temperatures, seedlings generally need about 50 days; in cold seasons they need 60—80 days, and in hot seasons about 40 days.

3. Flowering and fruit-setting stage

This period requires 15-30 days. Early-maturing cultivation or high-temperature cultivation requires a shorter time, and the reverse requires a longer time.

4. Fruiting stage

From fruit setting on the first inflorescence to the completion of harvesting all fruits is the fruiting stage. In spring it takes 70—80 days, and in solar greenhouses it reaches 7—8 months. The fruiting stage of the tomato is the time when nutrients and water are needed the most, and it is also an important period for management.

How should tomatoes be fertilized during the flowering and fruiting stages?

1. The absorption of nutrients by tomatoes increases as the growth period advances. In the early growth stage, the amount of nutrients absorbed is small. From fruit setting on the first inflorescence onward, nutrient absorption increases rapidly, and by the full fruiting stage, nutrient absorption can account for 70%-80% of the total absorption.

The absorption of nitrogen, phosphorus, and potassium by tomatoes shows a straight upward trend. The absorption of potassium is nearly twice that of nitrogen, and the absorption of calcium is similar to that of nitrogen.

2. Base fertilizer. For open-field tomato cultivation, base fertilizer should be applied heavily, that is, on the basis of applying organic fertilizer, 35-40 kg of nitric phosphorus potassium fertilizer should be applied per mu as base fertilizer.

For topdressing, when the first fruit truss swells, apply 20 kg of nitric phosphorus fertilizer per mu together with watering, and after the first fruit truss is harvested, apply 20 kg of nitric phosphorus fertilizer per mu as full-fruiting fertilizer. During the full fruiting stage, spray a mixed solution of 20% nitric phosphorus fertilizer, 1% potassium dihydrogen phosphate, 0.1% zinc sulfate, and 0.25% boric acid once every 7-10 days, which can significantly increase the yield of tomatoes and the content of vitamin C.

What are the symptoms of nutrient deficiency in tomatoes and how should they be addressed?

1. Potassium deficiency: Tomatoes need more potassium during growth. When the potassium supply in the soil is insufficient, fruit development comes at the expense of damaging the leaves. Usually after 3-4 trusses of fruit have set, potassium deficiency appears in the old leaves, and the symptoms are especially obvious. If the root system is well developed, the symptoms appear later. Sometimes potassium in the soil is sufficient, but in the middle and late stages the root absorption capacity declines and cannot provide enough potassium for fruit development and plant growth, so potassium deficiency symptoms still appear when the fruit ripens. Therefore, when cultivating, apply sufficient potassium fertilizer. Potassium fertilizer is prone to volatilization and leaching, so a combination of base application, topdressing, and foliar spraying should be adopted to ensure the supply of potassium in the middle and late stages;

2. Calcium deficiency: Calcium deficiency in tomatoes easily leads to blossom-end rot, which is a typical physiological disease. In production, attention should be paid to scientific and balanced fertilization. In addition to applying sufficient decomposed organic fertilizer as base fertilizer, a certain amount of superphosphate should also be used to prevent calcium deficiency in the soil. At the same time, deepen the soil, adopt plastic film mulching cultivation, and water in a timely manner. In particular, pay attention to a balanced supply of water during the fruiting stage, and strictly prevent alternating drought and moisture. If high temperature and drought occur during the flowering and fruiting stage, water in time. In the rainy season, pay attention to drainage after rain. In the early growth stage, apply nitrogen fertilizer steadily to avoid excessive vegetative growth. In addition, during the young fruit stage, remove blossom-end rot fruits in time to ensure the growth of healthy fruits;

3. Phosphorus deficiency: Insufficient phosphorus at the tomato seedling stage will cause the plant to grow slowly and the leaves to turn purple. Phosphorus has low mobility in the soil. Seedlings have a large demand for phosphorus, so it should be applied as base fertilizer and applied deeply. Phosphorus is easily fixed by soil colloids, so when applying phosphate fertilizer, it can be mixed with well-decomposed organic fertilizer or applied in concentrated furrows. Granular phosphate fertilizer can also be used to reduce its contact surface with the soil. In the middle and late stages of tomato growth, phosphorus can be supplemented by foliar spraying to improve the utilization rate of phosphate fertilizer;

4. Iron deficiency: The demand for iron in tomato growth is small, but iron still plays a very important role in tomato growth and development. When iron is insufficient, the leaves become chlorotic, but the veins, including the veins of small branches, remain green. Alkaline soil hinders the plant's absorption of iron, so iron fertilizer should be applied, but not excessively. Generally, ferrous sulfate is used, applied as base fertilizer at 2-7.5 kg/mu, or sprayed on the leaves as a 0.2%-1% aqueous solution;

5. Zinc deficiency: Insufficient zinc can cause the leaf tissue between the veins to turn yellow and develop into black spots or turn purple. Severe zinc deficiency can hinder plant growth. During the plant growth period, foliar spraying with a 0.02%-0.1% zinc sulfate aqueous solution can be used for prevention, effectively preventing the occurrence of zinc deficiency.